Generally, hydraulic excavators are well known as a construction machine. Hydraulic excavators of this sort are largely constituted by an automotive vehicular lower structure, an upper revolving structure rotatably mounted on the vehicular lower structure, and a working mechanism liftably provided in a front side of the upper revolving structure. A cab is built on a revolving frame of the upper revolving structure, and an operator's seat is provided within the cab to be taken by an operator. On certain cab-equipped hydraulic excavator, an air-conditioning unit is installed to send conditioned air into a cab through an air duct for providing an improved working environment.
Further, along with a wiper which is provided on a front window pane of a cab for wiping water droplets from the front window pane, a washer liquid spout nozzle is usually provided for the purpose of spurting a washer liquid onto the front window pane. The washer liquid spout nozzle is supplied with a washer liquid from a washer tank, which is located, for example, within an inner space of a cab (e.g., see Japanese Utility Model Laid-Open No. H7-35212). In some cases, a washer tank is located within an engine room which is provided in a rear side of a cab (e.g., see Japanese Patent Laid-Open No. 2002-13161).
By the way, in a case where a washer tank is located within a cab as in the above-mentioned Japanese Utility Model Laid-Open No. H7-35212, it becomes necessary to provide a washer tank installation space exclusively within the cab. However, in the case of small-size hydraulic excavator with a limited accommodation space within a cab, it is difficult to find an installation space for a washer tank. Therefore, if a washer tank is installed within a cab, it could obstruct the view field of an operator or stick out into the dwelling space to such a degree as to give an oppressive feeling to the operator.
Further, in the case of small-size hydraulic excavator, it is difficult to install a washer tank within an engine room as in above-mentioned Japanese Patent Laid-Open No. 2002-13161 because usually an engine room is crowded with engine and hydraulic equipments. Even if one has succeeded in installing a washer tank within an engine room, it becomes necessary to connect the washer tank with a nozzle by the use of a long hose, which has greater possibilities of being crushed or damaged en route to the hose, making it difficult to give an assurance in performance quality.